Disposable absorbent articles are broadly available and consumers are used to a high performance for the collecting and retaining of menses (in the case of sanitary napkins or panty liners) or for the collecting and retaining urine and fecal material (in the case of e.g. disposable diapers). However, consumers do not only expect a superior absorbency behavior, but place more and more emphasis on the wearing comfort of such articles.
Typically, such articles comprise multiple absorbent members, at least one member being primarily designed to store liquid, and at least one other member primarily designed to acquire and/or distribute liquid.
At least the storage member will often comprise super-absorbent material, which is admixed with the traditionally used pulp fiber material. Such super-absorbent materials can absorb many times (e.g. 10, 20 or 30 times) their own weight and are therefore very helpful when designing an article of improved fluid handling properties. Many recent products employ higher and higher concentrations of super-absorbent materials, that is concentrations in excess of 50% of the total weight of the storage member. These products achieve a high absorbing capacity with a very thin storage member and are thereby typically overall thin products. While super-absorbent materials can store very large amounts of liquid, they are often not able to distribute the liquid from the point of impact to more remote areas of the absorbent article and to acquire the liquid as fast as it may be received by the article.
For this reason acquisition members are used, which provide for the interim acquisition of large amounts of liquid and which often also allow for the distribution of liquid. Thereby the acquisition member plays a key role in using the whole absorbent capacity provided by the storage member.
An exemplary state of the art absorbent article, namely a sanitary napkin, is disclosed in WO 00/51651. The so-called “secondary topsheet” primarily provides for the liquid acquisition and distribution. The storage member is provided in the form of a core that can contain a high portion of super-absorbent polymer material.
State of the art absorbent articles in the form of disposable diapers are disclosed in the following co-pending applications: EP application no. 02017516.2 and EP application no. 03002677.7. The storage member of these articles may contain more than 50 weight-percent of super-absorbent polymer material, even more than 80% and in some embodiments even about 100% of the super-absorbent polymer material. While these articles are designed to have excellent fluid handling and fluid storage behavior, they may sometimes not be as comfortable to wear as some consumers would like it, namely those consumers interested in a premium product.
For achieving excellent fluid handling and fluid storage properties the respective storage members use super-absorbent materials, which are selected mostly with an emphasis on fluid handling properties. For example EP 304319 B1 (Goldman et al.) discloses the benefits of a relatively narrow distribution of the particle size of the super-absorbent polymers. The respective articles will preferably not comprise many fines, but relatively coarse particles. EP 752892 B1 (Goldman et al.) discloses an absorbent structure, which uses concentrations of super-absorbent particles in access of 60% and teaches to use super-absorbent particles of a relatively high porosity.
Most absorbent articles are designed such that the storage member is facing away from the wearer and such that the acquisition member separates the super-absorbent particles from the wearer. When conceiving the present invention, it was realized that the acquisition layer can play a very important role for imparting wearing comfort to an absorbent article, and namely to an absorbent article comprising a high concentration of relatively coarse super-absorbent particles. Comfort is a challenge in particular for those absorbent articles having a relatively narrow crotch as disclosed for example in U.S. Pat. No. 5,527,302 (Endres et al.) and for articles which are relatively thin as disclosed for example in EP 755649 B1 (Kellenberger et al.).
U.S. Pat. No. 5,997,980 discloses the use of hollow polyester fibers in nonwoven materials which are said to have good thermal recovery.
WO 98/22279 discloses acquisition layers for improved liquid handling in absorbent articles. As a preferred fluid handling material fibrous materials, which are preferably carded are disclosed. These fibers are chemically bonded by a resin. The fluid handling material is designed to achieve an acquisition performance of less than 2 seconds for the third impacting gush of liquid.
WO 99/00098 discloses a fluid acquisition/transfer layer for an absorbent article, which employs thermoplastic multi-component fibers and where the bonding is achieved by the addition of thermoplastic fibers, which are heat bonded.
WO 03/048440 discloses the use of helically crimped single polymer fibers, which preferably are bonded by thermal bonding techniques, in an absorbent article.
It is one objective of the present invention to provide an absorbent article, which has improved liquid handling characteristics as compared to the above disclosed articles.
In one further important aspect it is an objective of the present invention to provide an article, which is more comfortable to wear.
In another aspect of the present invention, it is an objective to provide an article, which is relatively thin and which may have a small crotch region.